Arsinic acids and process of making the same.



the Same; and we methylnitg'amino-phenyl arsinlc acid.

ways under our invention. In the first LORENZ son. or mauunnm, Ann

- .essreuoss ro 0. r. BOEHEINGER No Pfawing'.

To all whom it may concern I Be itknown that We, LORENZ A011 and ALBERT ROTH ANN, citizens of the German Empire, residing atMannheim and Heidelberg, Germany, respectively,have invented 1 certain new and useful Improvements in Arsinic Acids and the Process-0t Making do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the art of preparing arsinic acids and, more particularly, nitrated methylnitramino phenyl arsinic acids, the object beingto obtain starting materials from which arsenic compounds serving as valuable therapeutic agents and remedies and possessing a relatively low toxicity maiylb'e pre ared.

manu acturing one of the new arsinic' acids we subject dimethyl anilin arsini'coxid, which has been described in Ann/alert der Chem/2'6, vol. 270 (1892) on page 140, to the action ofa mixture of nitric and sulfuric acids, alsoknown as nitrating acid. This reaction results in the production of a wellcrystallizing nitro' compound to which the formula G,H,N,As0, is to be assigned. On titrating this bodyit was found that 1.00% grams of the same required 5.4 cubic centimeters of normal potassium hydrate (n-KOH) for complete neutralization, from which it follows that the acid is dibasic. Moreover, one nitro group may be split off when thecompound is treated in the nitrometer according to Lunge; hence this nitro group must be bound to the nitrogen of the amino group. The structure of this new acid is hence expressed in the following formula; I Y

and it is properly designated specifically as 3, 5-dinitro-4-methylnitramino benzene-larsinic acid and generically-as a 'dinitro- I be modified in two The above process may place it is not necessary to start with of the dimethylanilin arsenic oxid,.but in general, any arsenic compound of dimethylamhn ALBERT ROTHMANN, OF HEIDELBERG, GERMANY, & SOEHNE, 0F MANNHEIM-WALDHOF, GERMANY,

AESI'NiC ACIDS AND rnoonss or MAKING THE SAME.

Patented Oct. 7, 1913.

Application filed March 31, 1913. Serial 310.75%,668. I

which belongs to the same stage of oxidation as the arsenic oxid, and p-dimethylanilin-arsinic acid under the oxidizing influence of the nitrating acid, such as, for example, p-dimethylanilin arsenious chlorid, may be employed as starting material. Or the said chlorid may be proceeded from directly as the starting material. Moreover, all aromatic compounds 'of arsenic generally, which contain the group on N\R in the para position of the arsenic residue, and wherein B may denote hydrogen or the methyl group or an acyl residue, may serve as starting. materials. When such compounds undergo nitration, two nitro groups pass into the benzene nucleus, while the third nitro grou is bound to thenitrogen atom where it tl res the place of the hydrogen atom or of the methyl group or the acyl residue, while the arsenic residue, in case it did not already exist in the formof an arsinic acid, isoxidized to form the arsinic acid. It will thus be seen that in all of these cases, no matter how ditferent be the starting materials, the final product is obtained in the form of a dinitro-methylnitramino phenyl arsinic acid. From these arsinic acids, as has been stated, arsenic compounds having valuable tl1erapeutic properties may be obtained by reduction,

as has been set forth and claimed in;our concurrent application for Letters Patent United States, 686,843, filed March 26th, 1912.

To fully disclose our invention and to enable those skilled in the art to carry the same into effect, we will now describe in detail a number of examples embodying what we consider the preferred manner of carrying the same into effect. All proportions are understood to be by weight.

Emample l-Jv'eparatt'on of. an arsz' acid from pam-dimetlt z l-anlinarsenic 0m'd. -One part of .p-dimethyl-anilin-arsenic oX i'd is dissolved in 10 parts of concentrated sulfuric acid, and the solution added to a mixture of three parts concentrated nitric acid, of specific gravity-1.41, an parts of concentrated sulfuric acid at 0,

which yields Serial Number centigrade, water bathuntil no mineral acids. In

acids.

7 acid.4

the whole being .tlien'heated in a more'red vapors are evolved. After having cooled, the whole is poured onto about 20 parts of ice. The

nltrocompound is thus. thrown out as a light yellow substance, .which is then separated by siphoning, decairiting or otherwise, whereupon it is washed" with water and dried. The new compound 3, 5-dinitro-4- methyl-nitramino benzene-1, arsinic acid, has the formula given above. It is readilysoluble in hot acetone, hot alcohol and in glacial acetic acid and insoluble in dilute a solution of sodium hydrate, of sodium carbonate, or of sodium acetate it is readily soluble, being reprecipitated from suchsolutions with mineral It defiagrates when heated on platinum-foil.

Ewample 2Preparatz'0n of the same arsz'm'c acid from para-dimethyZ-am'Zz'n-drsenious 0lzZ0rz'aZ.-4 parts of para-dimethylanilin-arsenious chlorid are dissolved in 40; parts of concentrated sulfuric acid, and the solution is added to a mixture of 6 parts of concentrated sulfuric acid and 6 parts of a temperature -of from 0 to 10, centigrade, the whole being then heated to from 40 to 50, oentigrade, while stirring. Thereupon the mixture is allowed to cool and after cooling it is poured onto about 100 parts of ice, whereby the new acid dinitro methylnitramino phenyl 10- arsinic acid is thrown out and is then separated and purified as under Example 1.

Example 3Prepamtion of the arsz'm'c acid from I para dz'methg Z am'ltn a-rsz'm'c parts of para-dimethyl-anilin arsinic acid are dissolved in 4x0 parts of concentrated sulfuric acid and then nitrated as in Example 2 with nitrating acid. The rest of the process is. carried out as under EX- am le 2.

enerically considered the new process consists in treating witha nitrating reagent an aromatic compound and having the group preparing compounds containing arsenic which comprises subjecttain ng the group mg an aromatic compoundof arsenic con-.

in the para po ition, .where amonoin the para position' to the action of a nicontaining arsenic to the action ofa nitrating agent.

I CH3 7 -N R l g in the para position, where R is a monc, valent radical, to the action of a mixture of. concentrated sulfuric acid and concentrated w nitric acid.

3. The process of preparing compounds ,1

containing arsenic which consists sub-" jecting an aromatic compound of arsenic containing the grou in the para position, where; Ryis a rnono- 2,. valent radical, to the action of a;mixturezof ;85, concentrated sulfuric acid and concentrated nitricacid'under the influence of heat. 4. The process of preparing 'comp qunds g containing arsenic which consists in -gubjec'ting an aromatic compound of arsenic 9t containing thegroup on, r in the paraosition, where R is a monovalent radical: to the action of a mixture of concentrated sulfuric acid and concentrated nitric acid under the influence of heat, and then cooling and treating with ice.

5. The process of preparing compounds 1 containing arsenic which comprises subjectingan aromatic compound of arsenic containing the group.

. W N Cm trating agent. k r

The process of preparing compounds containing arsenic WhlCll comprisessubjecting an arsenic compound of dlmethyl-anilin 1 7. The process of 'reparmg compounds containing arsenic which comprises subjecting p-dimethyl-anilin-arsenic oxid to the action of a nitrating agent.

8. The processof preparing compounds containing arsenic whlch comprises subjecting p-dimethyl-anilin-arsenic oxid to the action of a mixture ofconcentrated sulfuric acid and concentratednitric acid with the aid of heat, and cooling afterithe reaction, has" proceeded to the desired extent.

9. As a new chemical compound dinitro-' methylnitramino-phenyl-p-arsinic acidL-ha've ing the vformula,

- nim ac-mmqemcgoua which s r ad y 'sqluble. iniiliata c rh alcohol and in glacial acetic acid, insoluble our signatures-in the presence of two witin dilute mineral acids, soluble in solutions nesses.

of sodium hydrate, of sodium carbonate and LORENZ ACH.

of sodium acetate, being precipitated from ALBERT ROTHMANN. 5 such solutions by mineral acids, and which Witnesses:

deflagrates when heated on platinum foil. JOSEPH PFEIFFER,

In testimony whereof we hereunto aflix LEOPOLD BLUM. 

